Read the entire series twice. Very entertaining overall. The ending has to be a let down, unless Stephen King really did figure out some secret of the universe that no one else knows.
I didn't know how it was going to end, but I was sure that it wasn't going to live up to the build up over the entire series. Nothing could do that, but what a cool story! 
I still think The Dark Tower would work best as an animation, with Clint Eastwood doing the voice of The Gunslinger, Whoopie Goldberg as Detta/Susannah, Harry Anderson (the judge on Night Court) as Eddie, and maybe the kid from Two and a Half Men as Jake. I had the whole cast figured out years ago with a different Jake cast, I forget which kid at the time I was thinking of.
Yeah, I agree that the ending was a letdown. Even though he warns you in the book not to read the ending because it might be a letdown. Phhtt.
I really liked a lot of it, but the best part IMO was Lud until the end of the mono.
Damn.
But... I doubt any film(s) that are 'cost effective' could do justice to the books.
*considering re-starting the series or maybe the Codex Alera series.
crabbsaline
Did you read the entire series? If so, how did you like the books?